Guides to marketplace alerts and buying used.

Where saved searches live in the Facebook app and on the website, how to turn their notifications on, how to delete one that will not delete, and what a saved search actually gets you.

Where the date sort is, why "newest first" still misses listings, the habits that surface new posts faster, and the only way to hear about a listing when it goes up without refreshing.

Craigslist can email you when a saved search has new results. The exact steps, how Craigslist decides when to send, the 20-result limit, and how to get Craigslist listings as a push notification instead.

The exact steps for OfferUp's two kinds of alerts from OfferUp's own help page, how to manage and delete them, what they fire for by OfferUp's own description, and how to get alerts that only fire for the exact item.

Facebook can notify you when a saved search gets new listings. Where the switches are on each device, what the alerts do and don't do, and what to do when they come too late.